Embodiments of the present invention relate generally to systems and methods for active compression decompression (ACD) cardiopulmonary resuscitation (CPR), and in particular to guided approaches which assist an operator in administering appropriate technique in an effective manner.
Sudden cardiac arrest is a major cause of death worldwide and can arise from a variety of circumstances, including heart disease and trauma such as electrical shock and suffocation. To improve a patient's chance of survival (and diminish the likelihood of brain and heart damage resulting from oxygen deprivation), it is important that measures be taken as soon as possible to at least partially restore the patient's respiration and blood circulation. Many years ago, techniques for external chest compression, generally referred to as cardiopulmonary resuscitation (CPR), were developed and have enjoyed great success in reducing mortality resulting from sudden cardiac arrest. Certain aspects of such techniques, however, have remained largely unchanged over recent years.
External chest compression relies on actively applying pressure to the patient's chest in order to increase intrathoracic pressure. Such pressure increase will induce blood movement from the region of the heart and lungs through the peripheral arteries, thus partially restoring the patient's circulation. Phase 1 of traditional CPR is referred to as the “active compression phase” where the chest is compressed by the direct application of external pressure. Phase 2, referred to as the “relaxation phase,” occurs when pressure is withdrawn and the natural elasticity of the patient's chest wall causes expansion. While such expansion is generally sufficient to refill the cardiac chambers with some blood, it is insufficient to ventilate the patient, i.e., fill the lungs with sufficient air to oxygenate the blood. Thus, conventional CPR further requires periodic ventilation of the patient, e.g., mouth-to-mouth ventilation, in order to provide the air necessary for blood oxygenation.
Manual CPR procedures generally require performers to lean over the patient and to apply pressure using the palms of their hands to the patient's sternum as the patient lies supine on a flat surface. If no one else is available, the performer must periodically shift position to ventilate the patient through a mouth-to-mouth procedure. Such manual procedures are thus very tiring to the performer and furthermore have been found to result in only marginal circulation.
Manual CPR procedures can also result in injury to the patient. For example, pressure applied by the palm of the hand can fracture the patient's sternum and/or ribs and cause other traumatic injury, especially if the performer's hand position is inadvertently shifted laterally to an improper location on the patient's chest. The performance and safety of CPR procedures can be enhanced through the use of various mechanical and automatic machines for applying external chest compression and optionally ventilating the patient by providing supplemental oxygen or air. The machines may be as simple as a “cardiac press” which is a manually operated lever which provides a mechanical advantage in performing chest compression. More sophisticated machines can provide chest compression and/or ventilation through a variety of other mechanisms, including the use of pressurized chambers for compressing the chest cavity. While such machines can be effective, their bulk, weight, and cost limit their availability. In particular, such machines are not widely available outside of medical facilities and their size is a deterrent to providing such equipment in emergency vehicles.
CPR is often administered in conjunction with other procedures which, taken together, are referred to as advanced cardiac life support (ACLS). Most commonly, CPR is administered while the patient undergoes both electrocardiographic monitoring (ECM) and electrical defibrillation. Although currently available CPR devices can provide real benefits to patients in need thereof, in some cases operator error or misuse may lead to ineffective treatment or patient injury. Hence, further advances would be desirable. For example, it would be desirable to provide improved systems and methods for guiding a system operator who may be involved with administering a treatment to a patient. Moreover, it would be desirable to provide systems and methods that help to ensure treatment is administered within desired or appropriate parameters. Embodiments of the present invention provide solutions that address the problems described above, and hence provide answers to at least some of these outstanding needs.